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Rochester 2G Rebuild

Discussion in 'Early CJ5 and CJ6 Tech' started by Danefraz, Jan 20, 2018.

  1. Jan 20, 2018
    Danefraz

    Danefraz Well-Known Member 2023 Sponsor 2022 Sponsor

    Chico CA
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    I did this once before, but I didn't really take a bunch of in-between photos.

    I will also supply part numbers as in a bit.

    This carb was really nothing wrong with it, other than it had water leak thru it in my shed, that caused the head to sieze, and well, it was a blessing of sorts...

    Anyway.

    Picture heavy.

    [​IMG]

    [​IMG]

    Here's the carb, completely removed. I like to use clean yogurt and fruit cups for many things. Some disassembly required. You may not want to remove the baffles and baffle rods. I wanted to make sure they were still serviceable (the rods were not excessively wobbly or worn.
    [​IMG]

    Not shown: bucket of Berrymans with the parts soaking in it's soupy goodness.
    After soaking these parts over night (the 1/3's of the carb body), high pressure water then air hose.

    I decided I didn't like the 'raisin' finish of the paint peeling off, so a buddy let me use his glass beading machine. I used blue tape and covered / plugged the important holes to minimize places the glass can get / clog.

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

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    [​IMG]

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    [​IMG]

    Currently polishing the carb throats, the baffles and the rods with the dremel and a wool wheel using a chrome polish (blue magic). I am NOT going to paint this again. I thought about having it powder coated... then I thought about using the Eastwood Carb Renew product, but just going to leave it.

    Off to dinner with friends and family.

    I have the original blue aluminum tag off this carb also.

    I am considering putting studs in the intake manifold to make putting it on easier.

    Parts list up next.
     
    homersdog, mike starck and Hellion like this.
  2. Jan 20, 2018
    Hellion

    Hellion Regurgitated

    Eastern TN
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    Many thanks for sharing and it’s looking good so far. I don’t like the painted finish either, natural is probably best.

    My 2G is slightly differently configured as the PO had the choke cable attached and activated from the passenger side of the carb and my throttle arm looks different too.
    Will your parts list contain the numbers for these external parts too?
     
    Last edited: Jan 20, 2018
  3. Jan 20, 2018
    mike starck

    mike starck Member

    salem,oregon
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    ARP makes some very nice carb studs just for what you need.I have used them on several engines
     
  4. Jan 20, 2018
    Walt Couch

    Walt Couch sidehill Cordele, Ga. 2024 Sponsor 2023 Sponsor 2022 Sponsor

    cordele, Ga.
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    The baffles and rods you speak of, could this be the throttle plates and throttle shaft?
     
  5. Jan 20, 2018
    Danefraz

    Danefraz Well-Known Member 2023 Sponsor 2022 Sponsor

    Chico CA
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    Yes. Thank you.
     
  6. Jan 21, 2018
    Danefraz

    Danefraz Well-Known Member 2023 Sponsor 2022 Sponsor

    Chico CA
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    Parts list as promised:

    QuadrajetParts.com

    Products
    ------------------------------------------------------
    1 x Rochester 2G Carburetor Rebuild Kit (R), Chevy 1970, Chevy/GMC Truck 1969-71, Jeep 1966-71 (4030R) = $28.95
    1 x Power Valve Assembly, OEM# 7011989 (3661A) = $11.95
    1 x Accelerator Pump Discharge Springs - (5 Pak) (1025A) = $2.50
    1 x Accelerator Pump Return Spring- (1040B) = $1.95

    This is the second time I've bought this list of parts. They worked so well the first time. I will likely save some bits and pieces for spares that were not impacted by water intrusion.

    The kit 4030R has EVERYTHING you should need except a power valve.

    you may not need the extra springs. I like having extras.
     
    Last edited: Jan 21, 2018
  7. Jan 21, 2018
    Danefraz

    Danefraz Well-Known Member 2023 Sponsor 2022 Sponsor

    Chico CA
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    More photos beamed up.

    Note: this is a series of photos. I'll later edit with comments where appropriate.

    The parts list that I provided comes with a diagram. It helps. Also has diagrams for the auto-choke models.

    I had a lot of fun getting the linkages back where they belong.

    Make a note of which check ball goes in which hole. There are two sizes, and in this kit, one is a 'pearl' colored plastic, one a steel version.

    This may be the last rebuild on this carb. There is wear on both the throttle plate shaft and some wear on the choke plate shaft. Acceptable for now. Not sure if it'd be worth bushing and repairing both - having done neither. If it gets to that point, I may have to go to the 4b holly with offy intake. Not likely given the weekend driver that this will be.

    SO, I just brought these back in from hitting them with 120psi of air through a skinny tube in every orifice I could get air into. All seems to flow freely. No grit, no sand, no mess or muss.

    Clean paper on workbench.

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    Notice the spring on the choke linkage. You need to add an extra twist to it to give it positive pressure so that it has some reasonable spring so that when you pull the choke to closed, then hit the accelerator, it pulls open from the vacuum draw.
    [​IMG]

    [​IMG]

    [​IMG]

    Note: in the top right corner, there's a screen that is finger-press fit into the well next to the accelerator pump well. Jets are #50 IIRC, and I'm re-using the power valve as it was sans junk and crud. have a new one if needed.
    [​IMG]
     
    Last edited: Jan 21, 2018
    47v6 likes this.
  8. Jan 21, 2018
    Danefraz

    Danefraz Well-Known Member 2023 Sponsor 2022 Sponsor

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    More photos

    important thing to note: there is a slight indentation / counter sunk area for the "main well inserts" that has a "D" shape to match their top.
    [​IMG]

    make sure the checkball, spring and T are in the right spot before you bold the venturi cluster down.
    [​IMG]

    spent some time on these with the wool dremel wheel and some "blue magic"
    [​IMG]

    Accelerator pump in the wrong position. Need to flip the hanger over (inner pump lever).
    [​IMG]

    Note: this shows the accelerator pump in the wrong position. Don't replicate it!
    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    A note here on the linkages. The half-moon shaped piece behind the throttle linkages that the choke linkage hooks too: It must be on the same side as the idle set screw, just a minor thing to know.
    [​IMG]

    I don't recall how far out the idle circuit screw must be turned out to start. Currently it's just in there. Will probably start about 2.5 turns out. I think last time, I started around 2 turns, then used a vacuum gauge to determine where it needed to be, then adjusted the idle screw...
    [​IMG]

    bottomed out these air mixture screws, then backed them out 2.5 turns.
    [​IMG]

    Couldn't resist bolting it up.
    [​IMG]
     
    Last edited: Jan 21, 2018
    47v6 likes this.
  9. Jan 21, 2018
    Danefraz

    Danefraz Well-Known Member 2023 Sponsor 2022 Sponsor

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    I'm crossing fingers on the float adjustment being good where I had it prior, using the same needle and seat as they were in great shape also. Saving the replacement parts for later if needed.

    The kit comes with the instructions and measuring stick to set the float to the right level based on model, etc.
     
    Last edited: Jan 21, 2018
  10. Jan 21, 2018
    Danefraz

    Danefraz Well-Known Member 2023 Sponsor 2022 Sponsor

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    The bolt holding the choke cable support seems stripped. UG. I think I'll have to dig out my thread fixin tools.
     
  11. Jan 21, 2018
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    Outstanding job on the rebuild and the write up! :)
     
  12. Jan 22, 2018
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

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    Yes, very good. (y)

    I expect the base is iron and originally was finished in black oxide. The body is zinc or zinc alloy AFAIK (so-called pot metal) and should have been the yellow chromate finish originally. I suspect the bare iron will rust and the bare zinc will corrode (making pits in my experience) so I would apply some kind of finish over the bead blasted surface. Eastwood has some kind of spray can to reproduce the yellowish chromate finish; you should be able to spray clear coat and not change the appearance. Supposedly Rustoleum has a fuel resistant clear coat in a spray can that's ok. 2K automotive clear coat would also work well, if you have that on hand.

    Another item to check is wear in the throttle shaft. That may not be an issue with the 2G since the base appears to be iron. Carburetors with a zinc base plate (like Motorcraft) have this problem a lot, and finding a carburetor that does not need the shaft bushed may be a problem. Erratic idle is the typical symptom - I expect you could test by spraying carb cleaner around the throttle shaft ends while trying to wobble it in the body. Changing idle speed would confirm wear.
     
  13. Jan 22, 2018
    Walt Couch

    Walt Couch sidehill Cordele, Ga. 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    [​IMG]
    The raised casting between the two Main Well tubes fits into a slot in the venturi assy. The kit should have provided a gasket that had a slot cut into it to fit over this raised casting. The gasket you used is going to cause a possible flow crossing between the Main Well tubes plus dis-figuring the casting of the venturi assy.
     
  14. Jan 22, 2018
    Danefraz

    Danefraz Well-Known Member 2023 Sponsor 2022 Sponsor

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    Tim,

    Yes, I have looked at the Eastwood stuff. I'm torn on it, mixed reviews on it's durability (spill fuel on it, etc.).

    Yes, zinc-potmetalish. Not aluminum. I was considering using a cold-bluing agent (like Oxpho Blue), and from what I understand, zinc metals have to be HOT (hair dryer, heat gun) for the bluing agent to work.

    the base is iron. IIRC it was black painted when I first obtained the jeep, and I soda blasted it. I considered using a cold-blueing on it. There is some wear on the shaft, brass looking shadows on the chromed finish. but currently more of a 'chrome plating' worn away vs. a lip that you can hang a fingernail on. the choke shaft though, it has a fingernail hanger of wear on it, but it's not as concerning since it's either 'open or closed' and mine is manual at that and does not seem to affect operation 'by easy fingers'.

    I'm short a 2k clear finish - I have similar to a 2k in a single stage spruce tip green or grey epoxy primer :)

    I haven't decided yet on a finish. Considered spraying with a light oil to slowly rust- finish it (not sure how well zinc's do that - looking into a bucket of zinc plated nails that have been there for years is a chalky mess).
     
  15. Jan 22, 2018
    Danefraz

    Danefraz Well-Known Member 2023 Sponsor 2022 Sponsor

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    Indeed. I looked at this, took the venturi cluster on / off a couple times. I'll likely look at it once more, there's one more gasket that is the same basic shape, with the rectangle for the raised casting cut out, that's the primary difference I see on the gaskets. There's also a gasket that doesn't fit the channel that has the apex xby the 1 1/8 marking correctly (different 2G application). I think there are +/- almost 10 gaskets that you don't use in this application, including a 3/8" thick coated cardboard riser that goes between the base of the carb and the intake manifold, but isn't the right shape (less holes per se).
     
  16. Jan 22, 2018
    Walt Couch

    Walt Couch sidehill Cordele, Ga. 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Depending on the manufacturer of the kit, there are some kits that have 3 to 4 different gaskets that will fit this area but all are slightly different from each. Some have missing or too many holes and others are thicker than others. Don't always assume the gasket that you take off is the correct one...:D
     
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  17. Feb 2, 2018
    fhoehle

    fhoehle Sponsor

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    Really nice write up.
     
  18. Feb 2, 2018
    Beach66Bum

    Beach66Bum 1966 Tuxedo Park Mark IV 2024 Sponsor

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    The firing order marked on the rotor cap is different ?? Correct me if I am wrong, isn't it 165432 going clockwise from the points window for the odd fire.
     
  19. Feb 2, 2018
    Danefraz

    Danefraz Well-Known Member 2023 Sponsor 2022 Sponsor

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    Roger! I marked the spots where the wires were previously - cap post to cylinder... I'll need to recheck them, I think the order is cast/stamped into the valve cover also.

    Thanks for the reminder / heads up. (New cap in a box of new parts also).
     
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